@polkadot/util/number/toHex.js

A collection of useful utilities for @polkadot

// Copyright 2017-2022 @polkadot/util authors & contributors
// SPDX-License-Identifier: Apache-2.0
import { hexFixLength } from "../hex/fixLength.js";
import { isNull } from "../is/null.js";
import { isUndefined } from "../is/undefined.js";
/**
 * @name numberToHex
 * @summary Creates a hex value from a number.
 * @description
 * `null`/`undefined`/`NaN` inputs returns an empty `0x` result. `number` input values return the actual bytes value converted to a `hex`. With `bitLength` set, it converts the number to the equivalent size.
 * @example
 * <BR>
 *
 * ```javascript
 * import { numberToHex } from '@polkadot/util';
 *
 * numberToHex(0x1234); // => '0x1234'
 * numberToHex(0x1234, 32); // => 0x00001234
 * ```
 */

export function numberToHex(value, bitLength = -1) {
  if (isUndefined(value) || isNull(value) || isNaN(value)) {
    return '0x';
  }

  const hex = value.toString(16);
  return hexFixLength(hex.length % 2 ? `0${hex}` : hex, bitLength, true);
}